librsb 1.3.0.2

Functions
autotune.cpp File Reference
Example programs and code

C++ example based on <rsb.hpp> for performance-benchmarking a matrix from file using RsbMatrix.tune_spmm(), for various right-hand side counts. More...

## Functions
template<typename nt_t >
void | bench (const std::string filename, rsb_flags_t order)
auto | main (const int argc, char *argv[]) -> int

## Detailed Description

C++ example based on <rsb.hpp> for performance-benchmarking a matrix from file using RsbMatrix.tune_spmm(), for various right-hand side counts.

Author
  Michele Martone

/*
Copyright (C) 2020-2022 Michele Martone
This file is part of librsb.
librsb is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
librsb is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public
License along with librsb; see the file COPYING.
If not, see <http://www.gnu.org/licenses/>.
*/
/*!
\ingroup rsb_doc_examples
@file
@author Michele Martone
@brief C++ example based on <rsb.hpp> for performance-benchmarking a matrix from file using RsbMatrix.tune_spmm(), for various right-hand side counts.
\include autotune.cpp
*/
#include <complex>
#include <array>
#include <vector>
#include <iomanip>
#include <iostream>
#include <string>
#include <rsb.hpp>
using namespace ::rsb;
template <typename nt_t>
void bench(const std::string filename, rsb_flags_t order) {
RsbLib rsblib;
rsb_int_t rnt { rsblib.get_num_threads() };
const rsb_int_t one {1};
const rsb_trans_t transA = RSB_TRANSPOSITION_N;
std::cout << "Librsb initialized with " << rnt << " threads." << std::endl;
RsbMatrix<nt_t> mtx(filename.c_str());
const rsb_flags_t flagsA {mtx.rsbflags()};
const bool is_sym = flagsA & ( RSB_FLAG_SYMMETRIC|RSB_FLAG_HERMITIAN ) ? 1 : 0;
const long long nnz_ops = ( is_sym ? 2 : 1 ) * ( mtx._is_complex() ? 8 : 2 );
const rsb_real_t mtxocc = mtx._get_storage_bytes();
std::cout << "Read matrix " << std::quoted(filename) << " : " << mtx._info() << std::endl << std::endl;
std::cout << "Matrix occupies " << mtxocc << " bytes " << std::endl;
for ( rsb_coo_idx_t nrhs : {1,2,4,50,100} )
{
const rsb_real_t opocc = sizeof(nt_t)*nrhs*(mtx.cols()+mtx.rows());
std::cout << std::endl << "Operands occupy " << opocc << " bytes now ( with " << nrhs << " nrhs )" << std::endl;
const rsb_nnz_idx_t nnzA {mtx.nnz()};
const char oc = ( order == RSB_FLAG_WANT_COLUMN_MAJOR_ORDER ? 'C' : 'R' );
const rsb_nnz_idx_t ldB {};
const rsb_nnz_idx_t ldC {};
const std::vector<nt_t> B(nrhs*mtx.cols(),1.);
std::vector<nt_t> C(nrhs*mtx.rows(),0.);
const nt_t alpha { 1.}, beta { 1.};
rsb_time_t dt, tt;
const rsb_blk_idx_t nsmA{mtx.blocks()};
mtx.spmm(transA,&alpha,nrhs,order,B.data(),ldB,&beta,C.data(),ldC); // caches warmup
dt = -rsb_time();
mtx.spmm(transA,&alpha,nrhs,order,B.data(),ldB,&beta,C.data(),ldC);
dt += rsb_time();
const auto flops_u = (nnz_ops*nnzA*nrhs)/dt;
std::cout << "rsb_spmm-" << nrhs << "-" << oc << " took " << dt << " s, for " << nnzA/dt << " nnz/s, " << flops_u << " flops/s\n";
if(true)
{
rsb_real_t sf = 1.0;
const rsb_int_t maxr = 10;
const rsb_time_t tmax = 20;
rsb_int_t tn {0};
// std::cout << "Turning on autotuning before each nrhs count..." << std::endl;
if(false)
rsblib.set_opt(RSB_IO_WANT_VERBOSE_TUNING, &one);
/*! [snip__tune_spmm] */
tt = -rsb_time();
mtx.tune_spmm(&sf,&tn,maxr,tmax,transA,&alpha,nrhs,order,B.data(),ldB,&beta,C.data(),ldC);
tt += rsb_time();
auto nnsmA {mtx.blocks()};
std::cout << "Tuning took " << tt << " s ( " << tt / dt << " ops ) and changed " << nsmA << " to " << nnsmA << " blocks" << std::endl;
mtx.spmm(transA,&alpha,nrhs,order,B.data(),ldB,&beta,C.data(),ldC); // caches warmup
/*! [snip__tune_spmm] */
dt = -rsb_time();
mtx.spmm(transA,&alpha,nrhs,order,B.data(),ldB,&beta,C.data(),ldC);
dt += rsb_time();
const auto flops_o = (nnz_ops*nnzA*nrhs)/dt;
std::cout << "rsb_spmm-" << nrhs << "-" << oc << " took " << dt << " s, for " << nnzA/dt << " nnz/s, " << flops_o << " flops/s\n";
if ( sf > 1.0 && flops_o > flops_u )
std::cout << "Tuning brought a " << std::max(flops_o / flops_u,sf) << " x speedup" << std::endl;
else
std::cout << "Tuning brought no speedup" << std::endl;
}
}
std::cout << "Done." << std::endl;
}
auto main(const int argc, char * argv[]) -> int
{
const std::string filename{ argc > 1 ? argv[1] : "../A.mtx"};
for ( rsb_flags_t order : { RSB_FLAG_WANT_COLUMN_MAJOR_ORDER,
#if defined(RSB_LIBRSB_VER_DATE) && (RSB_LIBRSB_VER_DATE) /* since 1.2.0.10 */
RSB_FLAG_WANT_ROW_MAJOR_ORDER
#endif
} )
{
#ifdef RSB_NUMERICAL_TYPE_FLOAT
bench<float>(filename,order);
#endif
#ifdef RSB_NUMERICAL_TYPE_DOUBLE
bench<double>(filename,order);
#endif
#ifdef RSB_NUMERICAL_TYPE_FLOAT_COMPLEX
bench<std::complex<float>>(filename,order);
#endif
#ifdef RSB_NUMERICAL_TYPE_DOUBLE_COMPLEX
bench<std::complex<double>>(filename,order);
#endif
}
}

## Function Documentation

## ◆ bench()

template<typename nt_t >

void bench | ( | const std::string | filename,
|  | rsb_flags_t | order
| ) |  |

[snip__tune_spmm]

[snip__tune_spmm]

## ◆ main()

auto main | ( | const int | argc,
|  | char * | argv[]
| ) |  | -> int